Energy-independent nonlocal potential model. II. The asymmetry term

We analyze the single-particle bound-state properties and the elastic scattering of protons and neutrons in various groups of isotopes, ranging from C up to Sn, by means of an energy-independent nonlocal optical model. The potential is obtained as an extension of the one used in the analysis of N=Z nuclei, the new term being a Lane-type potential with the same geometrical parameters as the isoscalar one. The radius of the potential is determined by the fit of single-particle energies and charge distribution in one nuclide of each group and it is given by R/sub N/=1.16(A-1)/sup 1/3/F. The well depths of the equivalent local potential are fitted to a large set of single-particle energies, measured in stripping and pick-up reactions, and show an energy dependence which is consistent with a unique nonlocal energy-independent potential having isoscalar nonlocality βapprox. =1F and isovector nonlocality β/sub T/approx. =1.6F. In particular, the bound-state data can determine the isovector part of the potential with fair accuracy, provided that proton and neutron, T> and T<, particle and hole states are analyzed: its average value at zero energy shows an increasing behavior from C to Mo. The nucleon point distribution and r.m.s. radii corresponding to this model potential have been calculated in various nuclei